There is a liquid crystal optical device including a liquid crystal optical unit that changes the distribution of the refractive index according to the application of a voltage by utilizing the birefringence of liquid crystal molecules. There is a display apparatus in which a liquid crystal optical device and an image display unit are combined. By changing the distribution of the refractive index of the liquid crystal optical unit, the display apparatus switches between a state in which the image displayed by the image display unit is caused to be incident on the eyes of a human viewer as displayed by the image display unit and a state in which the image displayed by the image display unit is caused to be incident on the eyes of the human viewer as multiple parallax images. Thereby, a two-dimensional image display operation and a three-dimensional image display operation are realized. High display quality is necessary for such a display apparatus.